fix(client): lint conformance for the preference services

Replace optional chains on always-present globals with the repo's
typeof guards (store.ts precedent), drop the non-null assertion by
failing loud on an impossible registry miss, and fix two arrow-parens
slips; cover the no-localStorage boot path in both service suites.

packages/client/locale/src/client/index.ts

@@ -161,8 +161,10 @@ export class LocaleService {
 
 /** Read the persisted locale id; unknown or unreadable values fall back to zh. */
 function restorePreference(): LocaleId {
+  // Non-browser runs (node e2e booting the client tree) have no localStorage.
+  if (typeof localStorage === 'undefined') return FALLBACK_LOCALE
   try {
-    const stored = globalThis.localStorage?.getItem(STORAGE_KEY)
+    const stored = localStorage.getItem(STORAGE_KEY)
     if (stored === 'zh' || stored === 'en') return stored
   } catch {
     // Storage access can throw (privacy mode); the default below covers it.
@@ -172,8 +174,9 @@ function restorePreference(): LocaleId {
 
 /** Persist the locale id; storage failures are non-fatal (preference resets next boot). */
 function persistPreference(id: LocaleId): void {
+  if (typeof localStorage === 'undefined') return
   try {
-    globalThis.localStorage?.setItem(STORAGE_KEY, id)
+    localStorage.setItem(STORAGE_KEY, id)
   } catch {
     // Storage access can throw (privacy mode / quota); the preference simply
     // does not survive the session.

packages/client/locale/tests/locale.spec.ts

@@ -1,5 +1,5 @@
 // @vitest-environment jsdom
-import { beforeEach, describe, expect, it } from 'vitest'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
 import { Context } from 'cordis'
 import type { LocaleSnapshot } from '@deepseek-ai/dsh-client-locale/client'
 import { LocaleService, STORAGE_KEY } from '@deepseek-ai/dsh-client-locale/client'
@@ -80,6 +80,18 @@ describe('LocaleService', () => {
     expect(make().svc.getLocale().active).toBe('zh')
   })
 
+  it('runs without localStorage (node boots): defaults on read, no-op on write', () => {
+    vi.stubGlobal('localStorage', undefined)
+    try {
+      const { svc } = make()
+      expect(svc.getLocale().active).toBe('zh')
+      svc.setLocale('en')
+      expect(svc.getLocale().active).toBe('en')
+    } finally {
+      vi.unstubAllGlobals()
+    }
+  })
+
   it('exposes the two shipped locales with self-described labels', () => {
     const { svc } = make()
     expect(svc.getLocale().locales).toEqual([